Polyphenylene ether molding compositions that include an alkenyl aromatic resin and an EPDM rubber

ABSTRACT

Novel molding compositions are disclosed which comprise a polyphenylene ether resin, an alkenyl aromatic resin and EPDM rubber.

This is a division, of application Ser. No. 111,983 filed Jan. 14, 1980U.S. Pat. No. 4,315,084.

BACKGROUND OF THE INVENTION

The term "polyphenylene ether resin" is descriptive of a well knowngroup of polymers that may be made by a variety of catalytic andnon-catalytic processes. By way of illustration, certain of thepolyphenylene ethers are disclosed in Hay, U.S. Pat. Nos. 3,306,874 and3,306,875, and in Stamatoff, 3,257,357 and 3,257,358. In the Haypatents, the polyphenylene ethers are prepared by an oxidative couplingreaction comprising passing an oxygen-containing gas through a reactionsolution of a phenol and a metal-amine complex catalyst. Otherdisclosures relating to processes for preparing polyphenylene ethers arefound in Fox, U.S. Pat. No. 3,356,761; Sumitomo, U.K. Pat. No.,1,291,609; Bussink et al, U.S. Pat. Nos. 3,337,499; Blanchard et al,3,219,626; Laakso et al, 3,342,892; Borman, 3,344,166; Horl et al,3,384,619; Faurote et al, 3,440,217; and disclosures relating to metalbased catalysts which do not include amines, are known from patents suchas Wieden et al, U.S. Pat. No. 3,442,885 (copper-amidines): Nakashio etal, U.S. Pat. No. 3,573,257 (metal-alcoholate or phenolate); Kobayashiet al, U.S. Pat. No. 3,455,880 (cobalt chelates); and the like. In theStamatoff patents, the polyphenylene ethers are produced by reacting thecorresponding phenolate ion with an initiator, such as a peroxy acidsalt, an acid peroxide, a hypophalite, and the like, in the presence ofa complexing agent. Disclosures relating to non-catalytic processes,such as oxidation with lead dioxide, silver oxide, etc., are describedin Price et al, U.S. Pat. No. 3,382,212. Cizek, U.S. Pat. No. 3,383,435discloses compositions of polyphenylene ethers and styrene resins. Allof the above-mentioned disclosures are incorporated herein by reference.

In Czechoslovakian Pat. No. 165,110 there are described compositions ofa polyphenylene ether resin; polystyrene or high impact polystyrene; andeither an ethylene-propylene copolymer polyisobutylene or an α-olefincopolymer. U.S. Pat. Nos. 3,943,191; 4,101,503; 4,101,504; 4,101,505 and4,102,850 all disclose compositions that include a polyphenylene etherresin and an alkenyl resin that is modified with an interpolymerizedEPDM rubber.

The applicants have found that when a composition of a polyphenyleneether, and an alkenyl aromatic resin is modified by the inclusion of asmall quantity of an EPDM rubber, the resulting compositions haveimproved Izod and Gardner impact strength and ductility as compared toanalogous compositions prepared with ethylene propylene rubber. Theinvention also includes compositions of a polyphenylene ether resin, aphosphate compound and an EPDM rubber and optionally a thermoplasticrubber.

Accordingly, it is a primary object of this invention to providethermoplastic molding compositions of a polyphenylene ether resin, analkenyl aromatic resin and an EPDM rubber.

It is also an object of this invention to provide a reinforced and flameretardant molding composition of a polyphenylene ether resin, an alkenylaromatic resin and an EPDM rubber

DETAILED DESCRIPTION OF THE INVENTION The compositions of the inventionscomprise:

(a) a polyphenylene ether resin;

(b) an alkenyl aromatic resin; and

(c) a rubbery interpolymer of a mixture of mono-olefins and a polyene.

The polyphenylene ether resins are polymers having units of the formula:##STR1## wherein Q is selected from the group consisting of hydrogen,hydrocarbon radicals, halohydrocarbon radicals having at least twocarbon atoms between the halogen atom and the phenyl nucleus,hydrocarbonoxy radicals and halohydrocarbonoxy radicals having at leasttwo carbon atoms between the halogen atom and the phenyl nucleus, Q' andQ" are the same as Q and in addition halogen with the proviso that Q andQ' are both free of a tertiary carbon atom and n is an integer of atleast 50.

The preferred polyphenylene ether resin is apoly(2,6dimethyl-1,4-phenylene) ether resin having an intrinsicviscosity of from about 0.40 dl/g to about 0.65 dl/g as measured inchloroform at 30° C.

The alkenyl aromatic resin will have at least 25% of its units derivedfrom monomers of the formula: ##STR2## wherein R¹ and R² are selectedfrom the group consisting of lower alkyl or alkenyl groups of from 1 to6 carbon atoms and hydrogen; R³, R⁴ and R⁵ are selected from the groupconsisting of chloro, bromo, hydrogen and (lower) alkyl of from 1 to 6carbon atoms; R⁶ and R⁷ are selected from the group consisting ofhydrogen and (lower) alkyl and alkenyl groups of from 1 to 6 carbonatoms or R⁵ and R⁶ may be concatenated together with hydrocarbyl groupsto form a naphthyl group. Styrene is the preferred alkenyl aromaticcompound.

An α,β-unsaturated cyclic anhydride may be copolymerized with the vinylaromatic compound. These compounds may be represented by the formula:##STR3## wherein the dotted lines represent a single or double carbon tocarbon bond, R⁷ and R⁸ taken together represents a ##STR4## linkage, R⁹is selected from the group consisting of hydrogen, vinyl, alkyl,alkenyl, alkylcarboxylic or alkenylcarboxylic of from 1 to 12 carbonatoms, n is 1 or 2, depending on the position of the carbon-carbondouble bond, and m is an integer of from 0 to about 10. Amounts from 0to 1 part per weight of anhydride per part by weight of alkenyl aromaticresin may be used. Examples include maleic anhydride, citraconicanhydride, itaconic anhydride, aconitic anhydride and the like.

Rubber may be employed in preparing the rubber-modified polymers of avinyl aromatic compound such as polybutadiene rubber, butyl rubber,styrene-butadiene rubber, acrylonitrile rubber, ethylene propylenecopolymers, natural rubber, EPDM rubbers, polysulfide rubber, propyleneoxide and the like. The rubber may be present at from 0.5 to 25 partsper weight per 100 parts of alkenyl aromatic resin

The EPDM rubbers are rubbery interpolymers comprising mixtures ofmono-olefins and a polyene including those prepared from ethylene, analpha-olefin and a polyene. Preferred types comprise 10-90 mole percentof ethylene, 10-90 mole percent of an alpha-olefin containing 3-16carbon atoms, and 0.1-12 mole percent of a polyene that is anon-conjugated cyclic or open-chain diene having 5-20 carbon atoms.Especially preferred are those alpha-olefins having 3-10 carbon atomsand non-conjugated cyclic or open-chain dienes having 5-10 carbon atoms.

Useable EPDM rubbers include the ethylene-propylene-ethylidenenorbornene terpolymer and those described in Ritchie, Vinyl and AlliedPolymers, Vol. 1 page 121 (1968) which is incorporated by reference. Thepreferred EPDM rubbery interpolymers are those comprising ethylene,propylene and 5-ethylidene-2-norbornene; or ethylene, propylene and1,4-hexadiene; and of ethylene, propylene and dicyclopentadiene.

The compositions of the invention may comprise from 10 to 90 parts byweight and more preferably from 40 to 65 parts by weight of thepolyphenylene ether resin component; from 90 to 10 parts by weight andmore preferably from 35 to 60 parts by weight of the alkenyl aromaticresin; and from 1 to 15 and more preferably from 2 to 10 parts by weightof the rubbery interpolymer of a mixture of mono-olefins and a diene.All references herein to parts are to parts by weight.

If desired, reinforcing fillers may be added to the composition inreinforcing amounts such as from 1 to 40 parts by weight per 100 partsby weight of total composition of fibrous glass, quartz, metal fibers,wollastonite or the fillers mentioned in U.S. Pat. No. 4,080,351 column3 and 4, which is incorporated by reference. Flame retardants such asthose described in U.S. Pat. No. 3,833,535 which is incorporated in thecomposition of the invention may also be present in addition tonon-reinforcing fillers.

Phosphates may be utilized in combination with the polyphenylene etherand the EPDM rubbery interpolymers and optionally a thermoplasticrubber. Suitable phosphates include phosphates of the formula: ##STR5##and nitrogen analogs thereof where each Q represents the same ordifferent radicals including hydrocarbon radicals such as alkyl,cycloalkyl, aryl, alkyl substituted aryl, and aryl substituted alkyl;and combinations thereof provided that at least one of said Q's is aryl.Typical examples of suitable phosphates include, phenylbisdodecylphosphate, phenylbisneopentyl phosphate, phenylbis-3,3,5'-trimethylhexylphosphate), ethyldiphenyl phosphate, 2-ethylhexyl di(p-tolyl) phosphate,bis(2-ethylhexyl) p-tolylphosphate, tritolyl phosphate,bis(2-ethylhexyl)-phenyl phosphate, tri(nonylphenyl) phosphate,di(dodecyl) p-tolyl phosphate, tricesyl phosphate, triphenyl phosphate,halogenated triphenyl phosphate, dibutylphenyl phosphate,2-chloroethyldiphenyl phosphate, p-tolyl bis(2,5,5'-trimethylhexyl)phosphate, 2-ethylhexyldiphenyl phosphate, and the like. The preferredphosphates are those where each Q is aryl. The most preferred phosphateis triphenyl phosphate. A composition comprised of mixed triarylphosphates, with one or more isopropyl groups on the aryl rings, such asKronitex 50 supplied by FMC may also be utilized. Generally thesecompositions will comprise from 65-95 parts by weight of thepolyphenylene ether resin; from 35-5 parts by weight of the phosphateand from 1-15 parts by weight of the rubbery interpolymer of a mixtureof monoolefins and a polyene alone or in combination with athermoplastic rubber. If such a mixture is utilized, it should contain aminimum of 25% by weight of the rubbery interpolymer. The thermoplasticrubbers of the ABA type with or without a saturated midblock arerespectively described in U.S. Pat. Nos. 3,646,162 and 3,595,942 whichare incorporated by reference.

The compositions may be prepared by tumble blending the components withor without suitable reinforcing agents, stabilizers, pigments, fillers,flame retardants, platicizers or extrusion aids. The blended componentsmay then be extruded into a continuous strand, the strands are choppedinto pellets and the pellets may be molded to any desired shape.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

50 parts of poly(2,6-dimethyl-1,4-phenylene)ether¹, 50 parts of a highimpact polybutadiene modified polystyrene² and 5 parts of a modifier(either polyethylene, EPR³, or EPDM⁴) were extruded and molded. Forcomparison, a fourth blend was prepared with 1.5 instead of 5 parts ofpolyethylene. Each blend also contained 3 parts triphenyl phosphate, 1part diphenyl decyl phosphite, 0.15 parts of zinc sulfide and 0.15 partsof zinc oxide. Properties of the blends are listed in Table 1. The EPDMis much more effective in increasing impact strength of 50:50 blendsthan either polyethylene or EPR. 5% polyethylene caused extensivelamination of the blends; lamination was not observed with EPDM at thislevel.

                  TABLE 1                                                         ______________________________________                                                                                Gardner                                                 T.Y.   Elong.                                                                              Izod Impact                                                                            Impact                                Additive   Parts  (psi)  (%)   (ft.lbs/in.n.)                                                                         (in-lbs)                              ______________________________________                                        1. polyethylene*                                                                         1.5    9000   78    4.8      160                                   2. polyethylene*                                                                         5.0    7100   24    4.7      <10                                   3. EPR*    5.0    8100   36    4.9       80                                   4. EPDM    5.0    8600   60    5.7      150                                   ______________________________________                                         *Control                                                                 

EXAMPLE 2

A composition containing 90 parts by weight of apoly(2,6-dimethyl-1,4phenylene) ether resin and 10 parts oftriphenylphosphate, and blends of 90 parts of apoly(2,6-dimethyl-1,4-phenylene) ether resin, 10 parts oftriphenylphosphate and 5 parts of either Chemplex 1086 polyethylene,EPR¹ or EPDM² rubber were extruded, molded and tested, with the resultsshown in Table 2. Extensive lamination was observed in the blendscontaining polyethylene, but was less apparent in the blend containingthe EPR, and was not observed in the blend containing EPDM. Ductility(elongation), Izod impact and Gardner impact were improved by additionof Nordel 1500. Gardner impact strength was almost five times greaterwith Nordel 1500 than with any of the other additives.

                  TABLE 2                                                         ______________________________________                                                  T.Y.    Elong.  Izod Impact                                                                            Gardner Impact                             Additive  (psi)   (%)     (ft.lbs/in.n.)                                                                         (in-lbs)                                   ______________________________________                                         None     12,000  56      1.2      75                                         5. polyethylene*                                                                        10,500  52      2.5      <10                                        6. EPR*   10,600  90      2.4      80                                         7. EPDM   10,700  95      2.4      230                                        ______________________________________                                         *Control                                                                 

EXAMPLE 3

A composition of 91 parts poly(2,6-dimethyl-1,4-phenylene) ether, 9parts triphenylphosphate, 0.15 parts zinc sulfide, 0.15 parts zinc oxideand 10 parts of a triblock copolymer¹ was extruded and molded. Anotherblend was also prepared, of the same composition except that the 10parts of the triblock were replaced by a mixture of 5 parts of thetriblock and 5 parts of EPDM rubber², and a third with the 10 parts ofthe triblock replaced by 10 parts of EPDM. Properties of the blends aregiven in Table 3. The effect of replacing part or all of the triblockwith EPDM is a slight increase in Izod impact and a slight decrease inGardner impact strength.

                  TABLE 3                                                         ______________________________________                                                 T.Y.    Elong   Izod       Gardner                                            (psi)   (%)     (ft.lbs/in)                                                                              (in-lbs)                                  ______________________________________                                        8.  triblock*  10,400    63    3.8      230                                   9.  triblock/  10,100    76    4.6      210                                       EPDM 50/50                                                                10. EPDM        9,800    75    6.2      170                                   ______________________________________                                         *Control                                                                 

EXAMPLE 4

Compositions of 78 parts of poly(2,6-dimethyl-1,4-phenylene) ether; 22parts of triphenyl phosphate and 10 parts of the specified EPDM rubberwere extruded and molded along with a control blend that did not containany EPDM rubber.

    ______________________________________                                                       Izod Impact Gardner Impact                                     EPDM Rubber    (ft.lbs/1/8" notch)                                                                       (in-lbs)                                           ______________________________________                                        11. Nordel 1500    5.8         170                                            12. Epcar 847*     5.2         150                                            13. None**         1.2          50                                            ______________________________________                                         *Epcar 847 is a terpolymer of ethylene propylene and                          5ethylidene-2-norbornene containing about 65% ethylene, 30% propylene and     5% of 5ethylidene-2-norbornene.                                               **Control                                                                

EXAMPLE 5

Compositions of 55 parts poly(2,6-dimethyl-1,4-phenylene) ether; 45parts of an EPDM modified high impact polystyrene and 5 parts of Nordel1500 EPDM rubber was extruded and molded. A control composition that didnot contain nay of the Nordel 1500 EPDM rubber was also prepared. Thesecompositions had the following properties:

    ______________________________________                                                                Izod Impact Gardner                                   EPDM rubber   Elongation                                                                              (ft.lbs/1/8" notch)                                                                       Impact                                    ______________________________________                                        14.  Nordel 1500  77%       7.0       280                                     15.* None         81%       4.0       250                                     ______________________________________                                         *Control                                                                 

Obviously many variations will suggest themselves to those skilled inthe art from the above detailed description without departing from thescope or spirit of the invention. It is, therefore, to be understoodthat changes may be made in the particular embodiments of the inventionas defined by the appended claims.

We claim:
 1. A thermoplastic molding composition which consistsessentially of:(a) from 35-95 parts by weight of a polyphenylene etherresin; (b) from 65-5 parts by weight of a phosphate compound; and (c)from 1-15 parts by weight of a rubbery interpolymer of a mixture ofmonoolefins and a polyene.
 2. A thermoplastic molding composition asdefined in claim 1 wherein the polyphenylene ether resin ispoly(2,6-dimethyl-1,4-phenylene) ether resin, the phosphate is tri-arylphosphate and the rubbery interpolymer is derived from ethylene,propylene and 1,4-hexadiene.
 3. A thermoplastic molding composition asdefined in claim 1 wherein the polyphenylene ether resin ispoly(2,6-dimethyl-1,4-phenylene) ether resin; the phosphate is triphenylphosphate and the rubbery interpolymer is derived from ethylene,propylene and 5-ethylidene-2-norbornene.
 4. A thermoplastic moldingcomposition as defined in claim 3 wherein thepoly(2,6-dimethyl-1,4-phenylene) ether resin has an intrinsic viscosityof from about 0.40 dl/g to about 0.65 dl/g as measured in chloroform at30° C.
 5. A thermoplastic molding composition as defined in claim 3wherein the rubbery interpolymer comprises 10-90 mole percent ofethylene; 10-90 mole percent of propylene and 0.1-12 mole percent of5-ethylidene-2-norbornene.
 6. A thermoplastic molding composition whichconsists essentially of:(a) from 35-95 parts by weight of apolyphenylene ether resin; (b) from 65-5 parts by weight of a phosphatecompound; and (c) from 1-15 parts by weight of a mixture of (i) arubbery interpolymer of a mixture of monoolefins and a polyene and (ii)a thermoplastic rubber which is an ABA block copolymer having asaturated midblock.
 7. A thermoplastic molding composition as defined inclaim 6 wherein the ABA block copolymer is a styrene-butadiene-styreneblock copolymer.
 8. A thermoplastic molding composition as defined inclaim 6 wherein at least 25% by weight of (c) is the rubberyinterpolymer.